LockFile tries to acquire a read lock on the file f.

NewAlreadyLockedError returns a new AlreadyLockedError.

NewPidLock creates a new PidLock that can be used to get exclusive access to resources between processes.

PidExists checks if a process with the given PID exists and is running.

AlreadyLockedError manages info that clarifies why a lock has failed, but is still likely valid.

PidLock represents a lock file that can be used for exclusive access to resources that should be accessed by only one process at a time.